This invention relates to a mechanical support for failed gas struts and associated method. More specifically, it relates to such a mechanical support which may be easily installed upon a previously existing gas strut.
The use of gas struts has become relatively common. Such struts commonly use a cylinder and a piston rod. A charge of gas is initially placed within the cylinder. Retracting the gas strut from an extended position causes the gas pressure to build up. The gas pressure therefore causes the gas strut to normally assume an extended position.
Such gas struts are often used on the rear doors of hatchback automobiles although they have been used for automobile hoods or numerous other applications. In such hatchback arrangements, the unlocking or unlatching of the hatchback allows the pressurized gas charge to extend the gas strut such that the hatchback is held in an upper open position.
Unfortunately, the gas struts often lose their charge. Depending upon the circumstances, the loss of charge could cause the hatchback to fall down upon a person causing injury. Even in the absence of such danger, the failure of the gas strut makes it very hard for the consumer to continue to use the hatchback for placing items in the rear of his car.
The following U.S. patents are noted:
______________________________________ Number Inventor Issue Date ______________________________________ 3,883,126 Nicholls May 13, 1975 4,078,779 Molders March 14, 1978 4,155,433 Porter May 22, 1979 4,449,702 Hasegawa May 22, 1984 4,596,383 Howard June 24, 1986 4,634,170 Lach Jan. 6, 1987 ______________________________________
The Nicholls patent shows a gas spring having a latching means to prevent it from retracting accidentally.
The Molders patent discloses a pneumatic spring having a manually releasable stop to lock the spring in an intermediate position.
The Porter patent shows a positioning device with a stop which may be used to limit the range of adjustment provided by the positioning device.
The Hasegawa patent discloses a locking device for a gas strut which uses a resilient tubular member.
The Howard patent shows a cylinder which is used to block retraction of the piston rod of a gas spring. The cylinder does not block retraction of the gas spring or strut in the normal fully extended position. However, if the consumer wants to engage the lock, the consumer can extend the gas spring beyond its normal fully extended position such that a mechanical spring pulls the cylinder sideways until it blocks retraction of the gas spring.
The Lach patent discloses a mechanical support for a failed gas strut which may be snap fit to the gas strut or may be magnetically fit to the gas strut. The device includes breakaway sections which can be used to change the length of the device.
Although various prior devices have been generally useful at securing gas struts, they have been subject to one or more of several significant disadvantages. Complexity of construction and relatively high cost limit the applicability of some prior designs. Additionally, many prior designs require that the gas strut be specifically made to include the locking mechanism. That is, many prior designs are not suitable for providing a locking mechanism as an add-on device which can be used in conjunction with numerous of the currently marketed gas struts. Prior designs often have required additional manual manipulation in order to engage the locking mechanism. Some designs require significant time and concentration to perform possibly hazardous manipulations in order to unlock a locking mechanism. Considering that electrical components are sometimes placed at the end of the piston rod on many hatchback doors, it is disadvantageous to transfer thrust in a manner which might interfere with such electrical components as some designs may. Some prior mechanical supports, like that disclosed by the Lach patent, require that the support be completely removed from the gas strut and stored someplace when the gas strut is to be retracted.